Something about Thermal Sublimation Transfer Print Technology Which Is Important for Us
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What is dye sublimation print technology?
Dye sublimation printing, is chosen for its high quality photographic results. The printing process uses thermal transfer to transport varying amounts of colored dye pigments from a carrier to the PVC printing surface to which the dyes bond chemically.
Dye sublimation printers are known for their high quality photographic output. As the technology continues to be improved, dye sublimation printers are bringing cost-effective high quality digital printing into the mainstream.
How Do Dye Sublimation Printers Work?
This will either be a single four layered film with cyan, magenta, yellow, and gray pigments or four separate films for each color. Because the films contain the pigments, they will appear red, blue, green, and gray.
During the printing process, the films are placed on the paper and heated up by the print head. This will cause the pigments to leave the film and enter into the paper where it cools re-solidifies. This is the “sublimation” part. Sublimation means to heat something and turn it into a vapor, then to form it back into a solid. Because the pigments go from solid, to gas, and back to solid, there is little mess compared to ink.
What Makes A Dye-Sub Printer So Good?
There are two factors that contribute to the quality of dye sub printers. The first is continuous tone, and the other is un-dithered color.
The color produced by a dye-sub is the result of the mixing of pigments to get the actual color. This is in contrast to most other printing methods. It uses a tight group of colored dots which, when seen by the human eye from a distance, appear to be a color. Under magnification, the dots are clearly different colors, and when seen close up with the naked eye the picture appears grainy. Because only one color needs to be printed, a dye sub can place more dots on a paper. It takes a 1200 dpi printer to get the resolution a 300 dpi dye-sub printer is capable of.
Another difference, because the color sublimes on the paper instead of being laid down as little dots, the edges of each pixel are blurred. This gives the impression of blending for a more natural appearance. Dots from an inkjet leave large white gaps in between pixels, giving the impression of a grain.
Longevity is something we all want from our photographs. Because dyes sublimate into the paper instead of just being painted onto its surface, dye sub prints tend to resist fading and are often colorfast. Using special dyes and papers allow them to last even longer.
Why Doesn’t Everyone Use Dye Sub Printers?
For one thing, dye sub printers are typically far more expensive then comparable inkjet printers. You can buy a photo quality printer for half of what a comparable dye sub printer costs at the consumer level. On the professional level, the gap is much closer. But they can still be as much as a thousand dollars more expensive.
Dye sublimation printers also only do one thing well: photo quality full color images. They are neither practical for document printing nor are they as fast as inkjet printers. A dye sub printer takes about a minute to produce a print regardless of whether it’s a full color photo or a page of typed text. Because it still has to print each pixel thermally. An inkjet printer will only print the areas that need to be printed. So it can produce a full page of typed text in seconds. On the other hand, to produce a photographic quality print, an inkjet printer takes up to 10 minutes.
When it comes to printing on different kinds of papers, a dye sub is limited to papers and films. An inkjet printer can print to just about anything you can run through it, including cotton canvas, envelopes, cardstock, and foam backed presentation board.
Inkjet printers are more versatile, and since most people print both photographs and documents, they accept the trade-offs. Until recently, when low cost digital cameras and powerful computers became available to the general public, the only people who truly needed dye sublimation printing were photography studios, print houses, and art departments.
In some countries, dye sublimation is also known as “dye diffusion” printing.
Inside a dye-sublimation printer is a roll of transparent film with a repeating series of yellow (Y), magenta (M), cyan (C), black (K), and clear panels. The YMC panels contain thermally sensitive dyes corresponding to the three basic colors used in subtractive printing. By combining varying amounts of these dyes, any colour in the spectrum can be created, from white (no dye transferred on a white card) to black.
The black and clear panels are also used in this thermal printing process. But they operate in a different way called “mass transfer” in which all of the material is transferred once the carrier ribbon reaches the required transfer temperature. The black resin is used to apply dense black text and barcodes on top of the YMC color image. And the clear panel is used to put a protective overcoat over the entire printed image.
The thermal printing process uses a print head with many hundreds of individual heater elements which can each be separately. Controlled by software to transfer varying amounts of the YMC dyes. And all or none of the black (K) panel and the clear (O) panel as the appropriate panel passes under it.
In the case of the YMC panels, the individual temperature of the elements causes varying amounts of dye to be vapourised and to permeate the glossy PVC card surface where it forms bonds with the plastic molecules.
This is the “sublimation” part. Sublimation means to heat something and turn it into a vapour without going through the liquid phase. Because the pigments go from solid, to gas, and back to solid, there is little mess compared to inkjet printing which uses the liquid phase as part of the transfer process.
Because the color infuses and bonds with the card material, it is less vulnerable to fade and distortion over time.